1. SQL Server Integration Services 2008 &2012 www.sqljunkieshare.com

2.  The Lookup transformation performs lookups by joining data in input columns with columns in a reference dataset.  The Lookup transformation supports the following database providers for the OLE DB connection manager:  SQL Server  Oracle  DB2  It performs the Equi-join between source and reference dataset

3.  Equi-join between source or transformation input and reference dataset ◦ I.e at least one row should match between source and referenced dataset  The transformation supports join columns with any data type, except for DT_R4, DT_R8, DT_TEXT, DT_NTEXT, or DT_IMAGE  Lookup Transform is case sensitive

4.  Full cache mode  Partial cache mode  No cache mode

5.  Referenced data set is just queried once during pre execution phase  All the referenced dataset is loaded in to the memory before even loading the source data into the buffer  Fast, Less query’s to the reference dataset  It takes quiet bit of time depending up on the reference data set for package execution to begin

6.  Here lookup cache begin with empty when package execution begin, when a new row comes from source to lookup the transformation then query’s the reference dataset.  If matched, that row from the reference dataset is cached in memory for next time.  If not matched it will discard the row from memory or can saved in the miss cache buffer, by default row is dropped.

7.  Size limit for partial cache can be set in the advanced tab of lookup transform  Once cache is fill, lookup transform drops the last referenced rows from the cache cache

8.  As the name implies, in this mode the lookup transform doesn't maintain a lookup cache but, it keeps the last match around, as the memory has already been allocated. this means that look up transform still query’s the database for every row.

9.  Cache connection manager  Oledb connection manager